JP2013193467A - Vehicular track controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To continue vehicular track control when detection precision of driving lane information in front of a vehicle decreases.SOLUTION: A vehicular track controller (electronic controller 1) which detects own vehicle driving lane information ahead of a vehicle 10 and controls the vehicle 10 based upon the driving lane information, increases control response or damping of at least one of a vehicle body yaw rate, a vehicle body acceleration, and a vehicle body slip angle being under vehicular track control as compared with a case when driving lane information of reference detection precision is detected when detection precision of the driving lane information decreases below the reference detection precision or when the detection of the driving lane information is intermitted.

Description

  The present invention relates to a travel trajectory control device that supports travel in a lane of a host vehicle.

  2. Description of the Related Art Conventionally, a travel locus control device that captures an image of the front of a vehicle with an imaging device and assists the vehicle to travel in the lane using travel lane information based on the image information is known. For example, Patent Document 1 below describes this type of travel locus control device. In the travel locus control apparatus of Patent Document 1, the image information is handled as a flat screen, and two straight lines that approximate the left and right white lines of the road on the flat screen are obtained. Then, a first shift in the horizontal direction on the plane screen between the intersection point on the extension line of these two straight lines and the center line of the plane screen is obtained, and the horizontal position at a predetermined distance from the intersection point vertically downward on the plane screen is obtained. A second shift in the horizontal direction on the plane screen between the midpoint between the left and right white lines on the straight line and the center line of the plane screen is obtained. In this travel locus control apparatus, the steering control amount for the steering wheel is determined using the first deviation as the deviation of the yaw angle of the vehicle and the second deviation as the lateral deviation of the vehicle. According to the technique described in Patent Document 1, even if the depression angle of the imaging device changes due to a change in the pitch of the vehicle, it is possible to accurately determine the deviation or lateral deviation of the yaw angle of the vehicle. Controllability can be improved. Patent Document 2 listed below is a technology for dividing image information in front of a vehicle, obtaining reliability of lane recognition for each section, performing vehicle control based on the reliability, and driving the vehicle in a lane. Is disclosed. In the technique described in Patent Document 2, when the reliability of lane recognition in the distance of the vehicle is low, only the lane recognition result in the vicinity of the vehicle where lane recognition is relatively easy and high reliability can be obtained. The vehicle is controlled based on the above. Further, in Patent Document 3 below, when the illumination state of the headlamp estimated based on the attitude angle of the vehicle becomes good, the control sensitivity of the vehicle control for preventing lane departure is increased while the illumination state deteriorates. A technique is disclosed in which vehicle control for preventing lane departure is appropriately performed according to the irradiation state by lowering the control sensitivity.

JP 2005-145402 A JP 2011-073529 A JP 2008-308091 A

  By the way, the imaging apparatus may be difficult to acquire distant image information, for example, only the latest image information can be obtained depending on the environment around the vehicle. In that case, since the detection accuracy of the travel lane information in front of the vehicle is lowered, it is difficult to distinguish a far travel lane compared to the latest travel lane. For example, in the technique described in the above-mentioned Patent Document 1, no consideration is given to the case where the detection accuracy of such far-off travel lane information deteriorates, and it is impossible to travel while keeping the vehicle in the lane. there is a possibility. Here, in the technique described in Patent Document 2, if even image information in the vicinity of the own vehicle can be obtained with high accuracy, only the section becomes highly reliable. Therefore, based on the image information of the section, Driving in the lane becomes possible. However, it can be assumed that even image information in the vicinity of the vehicle cannot be detected due to, for example, the detection signal being interrupted. In this case, the vehicle may not be able to travel in the lane. Further, in the technique described in Patent Document 3, if the headlamp illumination state is poor at night, the control sensitivity of the vehicle control for preventing lane departure is lowered, so that the vehicle travels in the lane at that time. May not be possible. Conventionally, the traveling locus control has to be interrupted when it becomes difficult to maintain traveling in the lane of the own vehicle.

  Therefore, the present invention provides a travel locus control device that can improve the disadvantages of the conventional example and can continue the travel locus control even when the detection accuracy of the traveling lane information in front of the vehicle is lowered. Objective.

  In order to achieve the above object, the present invention provides a travel locus control device that detects travel lane information of a host vehicle in front of a vehicle and controls the vehicle based on the travel lane information. When the detection accuracy is lower than the detection accuracy or when the detection of the travel lane information is interrupted, the vehicle body yaw rate, the vehicle body lateral acceleration or the vehicle body during the travel locus control is compared with the case where the travel lane information with the reference detection accuracy is detected. It is characterized by increasing at least one control response or damping of the slip angle.

  Here, it is desirable that the control responsiveness or the damping is increased as the detection accuracy of the travel lane information is lower than the reference detection accuracy.

  Further, when the control responsiveness and the damping cannot be increased, it is desirable to reduce the vehicle speed.

  The travel locus control apparatus according to the present invention increases the control responsiveness or damping of at least one of the vehicle body yaw rate, vehicle body lateral acceleration, or vehicle body slip angle during the travel locus control, thereby detecting the detection accuracy of the travel lane information as a reference. Even when it is lower than the accuracy or when the detection of the travel lane information is interrupted, it is possible to avoid lane departure. Therefore, according to this travel locus control device, the travel locus control can be continued even in such a case.

FIG. 1 is a diagram illustrating an example of a vehicle to which a travel locus control apparatus according to the present invention is applied. FIG. 2 is a block diagram illustrating the travel locus control. FIG. 3 is a diagram for explaining a case where the detection accuracy of travel lane information is lower than the reference detection accuracy. FIG. 4 is a flowchart for explaining the operation of the travel locus control apparatus according to the present invention.

  Embodiments of a travel locus control apparatus according to the present invention will be described below in detail with reference to the drawings. The present invention is not limited to the embodiments.

[Example]
An embodiment of a travel locus control apparatus according to the present invention will be described with reference to FIGS.

  First, an example of a vehicle 10 and a vehicle control system to which the travel locus control apparatus is applied will be described with reference to FIGS. 1 and 2. The vehicle control system includes various vehicle control devices such as the following driving support system and a travel locus control device that support the operation of the driver (FIG. 2). For example, a variable gear ratio steering (VGRS) system, an electric power steering (EPS) system, a rear wheel steering (ARS: Active Rear Steer) system, etc. are installed as the driving support system. Yes. The control functions of various control devices such as the travel locus control device are provided as a function of the electronic control unit (ECU) 1.

  The vehicle 10 is provided with a steering device 20, a steering torque generating device 30, a steering device 40 for front wheels Wfl and Wfr, and a steering device 50 for rear wheels Wrl and Wrr.

  The steering device 20 includes a steering wheel 21 operated by a driver, a rotating shaft (hereinafter referred to as “steering shaft”) 22 coupled to the steering wheel 21, and a steering angle for detecting a steering angle of the steering wheel 21. And a detection unit 23. The steering angle detector 23 detects, for example, the rotational movement amount or rotational angular velocity of the steering shaft 22 and transmits the detection signal to the electronic control device 1. The electronic control unit 1 calculates the steering angle of the steering wheel 21 based on the detection signal.

  This steering device 20 is of a so-called steer-by-wire system in which there is no mechanical connection between the steering wheel 21 and the front wheels (steering wheels) Wfl, Wfr. The electronic control unit 1 calculates the target turning angle of the front wheels Wfl and Wfr, and transmits the calculation result to the turning device 40 of the front wheels Wfl and Wfr. As the target turning angle, an angle according to the steering angle of the steering wheel 21 by the driver, an angle according to the steering angle and vehicle state information (vehicle speed, vehicle yaw rate, vehicle lateral acceleration, etc.), etc. are set. .

  The VGRS system (gear ratio variable steering system) is configured using the steering device 20 and the electronic control device 1. This VGRS system corresponds to a form of turning angle control using the vehicle state information described above, and controls the turning angles of the front wheels Wfl and Wfr according to the steering angle of the steering wheel 21 and the vehicle speed. The electronic control unit 1 performs control so that the turning angle increases with respect to the steering angle as the vehicle speed decreases, and controls so that the turning angle decreases with respect to the steering angle as the vehicle speed increases.

  The steering torque generator 30 applies steering torque to the steering wheel 21 via the steering shaft 22. The steering torque generating device 30 generates the steering torque by, for example, power of an electric motor, and forms an EPS system (electric power steering system) together with the electronic control device 1. For example, the steering torque generator 30 applies a steering assist torque in the same direction as the steering direction of the driver's steering wheel 21 to the steering shaft 22, so that the steering torque input by the driver to the steering wheel 21 is applied. Reduce. Further, the steering torque generator 30 can also apply a steering reaction torque in the direction opposite to the steering direction of the driver's steering wheel 21 to the steering shaft 22. For example, the steering torque generator 30 can be configured to generate a steering assist torque when the vehicle speed is equal to or lower than a predetermined vehicle speed, and to generate a steering reaction torque when the vehicle speed exceeds a predetermined vehicle speed. The steering reaction torque at that time is for suppressing a sharp steering operation of the steering wheel 21 during high-speed traveling. The electronic control device 1 sets the direction and magnitude of the steering torque according to the control mode, and controls the steering torque generating device 30.

  The steering device 40 for the front wheels Wfl and Wfr turns the front wheels Wfl and Wfr to the target turning angle based on a command from the electronic control device 1. The steering device 40 includes shafts 41L and 41R connected to the front wheels Wfl and Wfr, an actuator 42 that generates power such as an electric motor, and the power is converted into a steering force and transmitted to the shafts 41L and 41R. A turning force transmission mechanism 43.

  The turning force transmission mechanism 43 includes, for example, a ball screw nut formed on the inner peripheral surface of the rotor of the electric motor or attached to the rotor, a spiral ball screw portion formed on the outer peripheral surface of the shafts 41L and 41R, and The ball screw mechanism includes a plurality of balls disposed between the ball screw nut and the ball screw portion. In this type of turning force transmission mechanism 43, the ball screw nut rotates in the circumferential direction in accordance with the power of the actuator 42, and the shafts 41L and 41R are linearly moved in the left direction or the right direction of the vehicle 10 according to the rotation direction. Thus, the front wheels Wfl and Wfr at both ends of the shafts 41L and 41R are steered to the target turning angle.

  Further, the turning device 40 is provided with a turning angle detector 44 that detects the turning angles of the front wheels Wfl and Wfr. The turning angle detection unit 44 detects, for example, the amount of movement of the shafts 41L and 41R in the vehicle left-right direction, and transmits the detection signal to the electronic control device 1. The electronic control unit 1 calculates the turning angle of the front wheels Wfl and Wfr based on the detection signal.

  The ARS system (rear wheel steering system) is configured using the rear wheel Wrl, the steering device 50 for the Wrr and the electronic control device 1. The steering device 50 for the rear wheels Wrl and Wrr includes shafts 51L and 51R similar to those for the front wheels Wfl and Wfr, an actuator 52, a steering force transmission mechanism 53, and a steering angle detector 54. The steering device 50 turns the rear wheels Wrl and Wrr to a target turning angle based on a command from the electronic control device 1. As the target turning angle of the rear wheels Wrl and Wrr, for example, an angle corresponding to the steering angle of the steering wheel 21 and the vehicle state information is set. Further, the target turning angles of the rear wheels Wrl and Wrr are set to the same phase as or opposite to the turning angles of the front wheels Wfl and Wfr when turning all the wheels.

  In addition, the vehicle control system is provided with a travel locus control device that performs the travel locus control of the host vehicle. The travel locus control is so-called lane keeping assist control in which the vehicle travels while being maintained in the lane. In this travel trajectory control, the travel lane information of the host vehicle (information that can recognize the lane in which the host vehicle is present, based on the image information in front of the host vehicle captured by the imaging device 61, and the left and right white lines and yellow lines Lane shape (that is, linear information such as road shape) is detected, and the deviation (so-called lateral deviation) between the center of the lane and the own vehicle position that are equidistant from the left and right white lines is determined, and the possibility of lane departure Determine the presence or absence. For the imaging device 61, for example, an image sensor including an image sensor such as a CCD element or a CMOS element is used.

  When this traveling locus control is executed, traveling lane information (reference traveling lane information) that is a reference within a predetermined distance from the host vehicle is required. The predetermined distance is preset for each vehicle type. In the following, the travel locus control executed based on the reference travel lane information is referred to as normal travel locus control, and the image information necessary for detecting the reference travel lane information is referred to as reference image information.

  This travel locus control mainly performs lane departure warning control and lane keeping support control.

  The lane departure warning control means that when there is a possibility of lane departure, a warning or a display to that effect is displayed or a small steering torque is applied to the steering wheel 21 for a short time. This alerts the driver and prevents lane departure. The steering torque is a torque in a direction to return the vehicle 10 to the vicinity of the center of the lane, and is generated by the steering torque generator 30 described above.

  In the lane keeping assist control, when it is determined that there is a possibility of lane departure, a small steering torque is continuously applied to the steering wheel 21 so that the vehicle 10 can be easily returned to the vicinity of the center of the lane. Operation support is provided. Also in this control mode, the steering torque is a torque in a direction to return the vehicle 10 to the vicinity of the center of the lane, and is generated by the steering torque generator 30 described above. Further, in this lane keeping support control, when it is determined that there is a possibility of lane departure, the front wheel Wfl, Wfr or the rear wheel Wrl, Wrr is set so that the lateral deviation becomes 0 or falls within a predetermined value. It is also possible to return the vehicle 10 to the vicinity of the center of the lane by controlling at least one of the turning angles. Still further, the lane keeping assist control controls the turning angle of at least one of the front wheels Wfl, Wfr or the rear wheels Wrl, Wrr so that the lateral deviation is kept within 0 or within a predetermined value, so that the vehicle 10 It is also possible to drive while maintaining the vicinity of the center of the vehicle.

In this travel locus control, when performing the turning angle control as described above, at least one of the target vehicle body yaw rate γ _tgt , the target vehicle body lateral acceleration Yg _tgt or the target vehicle body slip angle β _tgt is set, The target steering torque and target turning angle are determined within a range that satisfies the set value. For example, the target vehicle body yaw rate γ _tgt is set to a value that suppresses the behavioral instability of the vehicle 10. It is preferable that the set value of the target vehicle body yaw rate γ _tgt has a width within a range that satisfies the conditions such as suppression of behavioral instability.

  By the way, in the imaging device 61, the imageable range may be narrower than the reference image information depending on the environment around the vehicle. At this time, the range of the detected travel lane information is narrower than the reference travel lane information. That is, when the detection accuracy of the image information is lower than the detection accuracy of the reference image information (reference detection accuracy), the detection accuracy of the travel lane information is also lower than the detection accuracy of the reference travel lane information (reference detection accuracy). When the detection accuracy of such travel lane information is lower than the reference detection accuracy, the electronic control unit 1 calculates the lateral deviation based on the travel lane information near the recognizable vehicle, and the target steering torque and the target The trajectory control is executed with the turning angle set, and the lateral deviation calculation and the travel trajectory control are performed again after the travel lane information ahead is recognized. In other words, in this case, these calculation processes must be repeated in a short cycle. Depending on the calculation cycle of the electronic control device 1 and the control responsiveness on the vehicle 10 side, the vehicle 10 may deviate from the lane, or control may be performed. There is a risk of divergence. For this reason, conventionally, when the detection accuracy of the travel lane information is lower than the reference detection accuracy, the travel locus control is interrupted. Conventionally, the traveling locus control is also interrupted when detection of the traveling lane information is interrupted. On the other hand, in this embodiment, the traveling locus control is continued even when the detection accuracy of the traveling lane information is lower than the reference detection accuracy or when the detection of the traveling lane information is interrupted.

  Here, as a factor that the detection accuracy of the image information is lower than the reference detection accuracy, for example, the weather can be considered. Generally, if only one reference image information is set for the imaging device 61, for example, the reference image information is set on the basis of a good visibility condition during sunny daytime or cloudy day, but fog is generated. It is not set at the time of visibility deterioration conditions such as nighttime when the driving lane information can be recognized from the image information only when the headlight is irradiated or when it is raining. This is because it is difficult to photograph far away when the visibility is deteriorated than when the visibility is good. In this case, the electronic control device 1 determines that the detection accuracy of the image information is lower than the reference detection accuracy based on the input information from the imaging device 61, or the travel detected from the image information. When it is determined that the detection accuracy of the lane information is lower than the reference detection accuracy, it may be determined that the surrounding environment of the current vehicle is the visibility deterioration condition. For example, FIG. 3 illustrates a state where the previous road shape is not known due to poor visibility (the solid line is an actual road shape, and the two-dot chain line is an example of a road shape that can be estimated).

  In that case, if a raindrop sensor is provided in the vehicle 10, when the raindrop is detected by the raindrop sensor, it is determined that the detection accuracy of the image information and the traveling lane information is lower than the reference detection accuracy. You can do it. The raindrop sensor is a sensor that detects rain, and is used to automatically operate the wiper during rain. In the case of rain, reference image information may be obtained if the amount of rainfall is small. For this reason, the electronic control unit 1 determines that the amount of rainfall is so large that, for example, the reference image information cannot be obtained when the wiper operation mode is “strong”, and the detection accuracy of the image information and the traveling lane information is the reference. It may be determined that the detection accuracy is lower than the detection accuracy.

  In addition, it may be impossible to capture the reference image information due to the condition of the travel path. This is because, for example, the imaging device 61 cannot capture images as far as necessary for acquiring the reference image information in a turning circuit with a small curvature radius (road turning radius) or near the top of a steep uphill slope. In this case, the electronic control unit 1 is allowed to determine the travel path based on the map information such as the car navigation system and the own vehicle position information, and the travel path in front of the eyes can obtain the reference image information and the reference travel lane information. When it is determined that there is no road, it may be determined that the detection accuracy of the image information and the traveling lane information is lower than the reference detection accuracy.

  In addition, the reference image information may not be captured by another vehicle in front. In this case, the electronic control unit 1 determines that the detection accuracy of the image information is lower than the reference detection accuracy based on the input information from the imaging device 61, and the travel lane information detected from the image information Is determined to be lower than the reference detection accuracy.

  Even during night driving, there is a possibility that the reference image information can be captured depending on the lighting environment around the vehicle. For this reason, in this case, it is determined that the reference image information and the reference lane information can be detected.

  On the other hand, when the detection of the driving lane information is interrupted, when the image information itself cannot be captured temporarily, even if the image information can be captured, the signal related to the image information is temporarily blocked on the communication path. The case where it is done. The communication path includes a communication path in the imaging apparatus 61, a communication path between the imaging apparatus 61 and the electronic control apparatus 1, and a communication path in the electronic control apparatus 1. In this case, when it is determined that the image information cannot be temporarily acquired or the image information cannot be temporarily transferred to the calculation of the travel lane information, the electronic control device 1 is determined to have detected that the travel lane information has been detected. That's fine. Further, the electronic control device 1 may determine that the detection of the traveling lane information is interrupted even when it is determined that the signal related to the detected traveling lane information cannot be temporarily transferred to the lateral deviation calculation.

  When the detection accuracy of the image information and the traveling lane information is lower than the reference detection accuracy, or when the detection of the image information and the traveling lane information is interrupted, the traveling locus control device determines the responsiveness of the vehicle motion during the traveling locus control. By raising the travel stability of the vehicle 10 during the travel locus control, the travel locus control is continued. Specifically, in this case, when the control response of at least one of the vehicle body yaw rate γ, the vehicle body lateral acceleration Yg, or the vehicle body slip angle β during the travel locus control is in a normal state (detection of image information or travel lane information). To increase the responsiveness of the vehicle motion during the traveling trajectory control. In that case, the control responsiveness is raised within a range where the vehicle behavior can be kept stable.

Here, with respect to the target vehicle body yaw rate γ _tgt , the target vehicle body lateral acceleration Yg _tgt and the target vehicle body slip angle β _tgt , the following arithmetic expressions 1-3 are respectively set. “Gγ” represents a yaw rate gain, “Gyg” represents a lateral acceleration gain, and “Gβ” represents a slip angle gain. “Δ” represents the steering angle of the steering wheel 21. “T” represents a time constant, and “s” represents a Laplace operator.

γ _tgt = Gγ * δ / (1 + T * s) (1)
Yg _tgt = Gyg * δ / (1 + T * s) (2)
β _tgt = Gβ * δ / (1 + T * s) (3)

For example, when the control responsiveness of the vehicle body yaw rate γ during the travel locus control is increased, the control responsiveness of the target vehicle body yaw rate _γtgt may be increased as compared with that in the normal state. This because, in order to increase the control response of the target vehicle body yaw rate gamma _tgt decreases the time constant T from the target vehicle yaw rate gamma _tgt of the normal state during the setting. Similarly, for the vehicle body lateral acceleration Yg during the travel locus control, in order to increase the control response, the control response of the target vehicle body lateral acceleration Yg _tgt may be increased as compared with the normal state. to reduce the time constant T from the target vehicle lateral acceleration Yg _tgt of the normal state when setting the vehicle lateral acceleration Yg _tgt. Similarly, when increasing the control response of the vehicle body slip angle β, it is only necessary to increase the control response of the target vehicle body slip angle β _tgt than in the normal state, so the target vehicle body slip angle β _tgt is _increased . When setting, the time constant T is made smaller than the target vehicle body slip angle β _tgt in the normal state. As described above, in this travel locus control apparatus, the target vehicle body yaw rate γ is a first method for increasing the control response of at least one of the vehicle body yaw rate γ, the vehicle body lateral acceleration Yg, or the vehicle body slip angle β during the travel locus control. _It is only necessary to increase at least one control response among _tgt , target vehicle body lateral acceleration Yg _tgt, or target vehicle body slip angle β _tgt .

  Further, the control response of the vehicle body yaw rate γ, the vehicle body lateral acceleration Yg, or the vehicle body slip angle β during the travel locus control is the control response of the above-described driving support system (at least one of the VGRS system, EPS system, or ARS system). It can also be raised by raising the sex from the normal state. The control responsiveness of the VGRS system can be improved by improving the follow-up performance with respect to the target turning angle at the target turning angle of the front wheels Wfl and Wfr and the actual turning angle of the front wheels Wfl and Wfr in this system. Further, the control responsiveness of the EPS system can be improved by increasing the follow-up performance with respect to the target steering torque in the target steering torque and the actual steering torque of the steering wheel 21 in this system. Further, the control responsiveness of the ARS system is increased by improving the follow-up performance with respect to the target turning angle in the target turning angle of the rear wheels Wrl and Wrr and the actual turning angle of the rear wheels Wrl and Wrr in this system. be able to. In this case, by increasing the control responsiveness of each of the VGRS system, EPS system, and ARS system compared to the normal state, the actual responsiveness increases in each system even if the target value is the same. At least one control response among the vehicle body yaw rate γ, the vehicle body lateral acceleration Yg, or the vehicle body slip angle β is higher than that in the normal state. That is, in this travel locus control apparatus, as a second method for increasing the control response of at least one of the vehicle body yaw rate γ, the vehicle body lateral acceleration Yg, or the vehicle body slip angle β during the travel locus control, the driving assistance to be controlled. The control responsiveness of the system (at least one of the VGRS system, the EPS system, or the ARS system) may be increased as compared with the normal state.

Further, the control responsiveness of the vehicle body yaw rate γ, the vehicle body lateral acceleration Yg, or the vehicle body slip angle β during the traveling locus control can also be increased by increasing the vehicle body roll rigidity than in the normal state. The vehicle 10 improves the response of the vehicle motion by increasing the body roll rigidity. Therefore, when the vehicle body roll rigidity is increased, the target vehicle body yaw rate γ _tgt , the target vehicle body lateral acceleration Yg _tgt and the target vehicle body slip angle β _tgt are in the normal state (the detection accuracy of the travel lane information satisfies the reference detection accuracy). Even if the same value as that at time) is set, the actual changes in the vehicle body yaw rate γ, the vehicle body lateral acceleration Yg, and the vehicle body slip angle β are faster than in the normal state. Therefore, the vehicle body yaw rate γ, the vehicle body lateral acceleration Yg, or the vehicle body slip angle β during the traveling locus control can be improved in control response than in the normal state by increasing the vehicle body roll rigidity than in the normal state. . Here, when a damping force control system (AVS: Adaptive Variable Suspension System) of a suspension damper is mounted on the vehicle 10, the vehicle body roll rigidity can be increased by controlling the damping force. Further, when an active stabilizer is mounted on the vehicle 10, the vehicle body roll rigidity can be increased by controlling the torsional rigidity of the stabilizer. As described above, in this travel locus control device, as a third method for increasing the control response of at least one of the vehicle body yaw rate γ, the vehicle body lateral acceleration Yg, or the vehicle body slip angle β during the travel locus control, the vehicle body roll stiffness is set. Just raise it.

Further, as a fourth method, the responsiveness in the target value calculation process of the driving support system to be controlled (at least one of the VGRS system, EPS system, or ARS system) and the target value of the driving support system are commanded. By increasing the total responsiveness, which is the sum of the responsiveness until the actual output after that, from the normal state, the vehicle yaw rate γ, the vehicle body lateral acceleration Yg or the vehicle body slip angle β during the traveling locus control At least one control responsiveness can be increased as compared with the normal state. That is, the total responsiveness refers to responsiveness from when image information is detected by the imaging device 61 until the target value is actually output. In this case, since it is sufficient that the total responsiveness is higher than that in the normal state, one of the responsiveness may be lower than that in the normal state. Here, the target values of the driving support system are the target vehicle body yaw rate γ _tgt , the target vehicle body lateral acceleration Yg _tgt , the target vehicle body slip angle β _tgt , the target steering torque, the target turning angle of the front wheels Wfl, Wfr, and the rear wheels Wrl, This corresponds to the driving support system to be controlled among the target turning angles of Wrr. The responsiveness in the process of calculating the target value is the responsiveness until the target value is calculated after the lane information, the lateral deviation, etc. are calculated after the image information is captured by the imaging device 61. Say.

  Further, in this travel locus control device, various filters may be mounted between the time when image information is captured by the imaging device 61 and the time when the driving support system to be controlled is controlled. For example, a low-pass filter that removes noise from image information. For this reason, in this case, as a fifth method, the control response of the filter (at least one filter when a plurality of filters are mounted) is increased, so that the vehicle body yaw rate γ during the travel locus control, the vehicle body At least one control responsiveness of the lateral acceleration Yg or the vehicle body slip angle β may be increased from that in the normal state.

  Furthermore, as a sixth method, by shortening at least one of various communication times in the travel locus control apparatus, the vehicle body yaw rate γ, the vehicle body lateral acceleration Yg or the vehicle body slip angle β during the travel locus control can be reduced. The control responsiveness of at least one of the above may be increased from that in the normal state. The communication time is, for example, a transmission cycle of image information from the imaging device 61.

  As described above, in this travel locus control apparatus, in order to increase at least one control response among the vehicle body yaw rate γ, the vehicle body lateral acceleration Yg, or the vehicle body slip angle β during the travel locus control from that in the normal state. The above first to sixth methods can be considered. Therefore, in this travel locus control device, when the detection accuracy of the travel lane information is lower than the reference detection accuracy or when the detection of the travel lane information is interrupted, at least one of the first to sixth methods described above. By executing this, at least one control response of the vehicle body yaw rate γ, the vehicle body lateral acceleration Yg, or the vehicle body slip angle β during the traveling locus control may be increased as compared with the normal state. By improving the control responsiveness in this way, the travel locus control device can improve the stability of the travel locus control even when the detection accuracy of the travel lane information is lower than the reference detection accuracy or when the detection of the travel lane information is interrupted. Therefore, the traveling locus control can be continued while avoiding lane departure. In addition, this travel locus control device can be realized with respect to such an effect without causing an increase in cost, such as addition of a sensor.

  Here, in this travel locus control device, the more the detection accuracy of the travel lane information is lower than the reference detection accuracy or the more frequent the frequency of detection of the travel lane information (for example, the number of discontinuities per unit time), It is desirable to increase the control response of at least one of the vehicle body yaw rate γ, the vehicle body lateral acceleration Yg, or the vehicle body slip angle β during the trajectory control from that in the normal state.

  Lane maintenance support control by this travel locus control device will be described with reference to the flowchart of FIG.

  In this example, a switch (not shown) is provided in the vehicle compartment to allow the driver to select whether or not to execute the travel locus control. The electronic control unit 1 determines whether or not an instruction to start the traveling locus control is given (step ST1). In this step ST1, if stop of the travel locus control is instructed by the switch, this process is repeated, and if execution of the travel locus control is instructed from the switch, input of information necessary for the travel locus control is input. Processing is performed (step ST2). The information necessary for the travel locus control includes image information received from the imaging device 61, information received from various sensors such as the yaw rate sensor 71 and the vehicle body lateral acceleration sensor 72, and the like.

  The electronic control unit 1 detects travel lane information from the image information (step ST3), and calculates a lateral deviation between the own vehicle and the lane and a road turning radius (road turning curvature) based on the travel lane information ( Step ST4).

  Further, the electronic control unit 1 determines the detection accuracy of the image information or the travel lane information (step ST5).

The electronic control unit 1 sets a target vehicle motion state based on the travel lane information, lateral deviation, and road turning radius (road turning curvature) (step ST6). The target vehicle motion state is at least one of the above-described target vehicle body yaw rate γ _tgt , target vehicle body lateral acceleration Yg _tgt or target vehicle body slip angle β _tgt , and the vehicle behavior during the travel locus control remains in a stable state. This is setting information for running. In this step ST6, when the detection accuracy in step ST5 is the reference detection accuracy, the target vehicle body yaw rate γ _tgt used in the normal travel lane control is calculated, and when the detection accuracy is lower than the reference detection accuracy, the normal travel The control response such as the target vehicle body yaw rate γ _tgt is set higher than that used in the lane control.

  Subsequently, the electronic control device 1 sets a control target value of a driving support system (at least one of a VGRS system, an EPS system, or an ARS system) to be controlled according to the target vehicle motion state (step ST7). . The control target value is the target turning angle of the front wheels Wfl, Wfr, the target turning angle of the rear wheels Wrl, Wrr, and the target steering torque of the steering wheel 21. The target steering torque is a steering reaction torque for the driver.

  The electronic control unit 1 controls the driving support system to be controlled based on the control target value (step ST8).

  The electronic control unit 1 determines whether or not an instruction to stop the travel locus control is given by the above switch (step ST9). If the switch remains in the execution instruction, the electronic control device 1 returns to step ST2 and returns to the travel locus. Continue control. On the other hand, when the stop instruction of the traveling locus control is given, the traveling locus control is stopped, and this calculation process is ended.

By the way, during the travel locus control, by increasing at least one damping (attenuation) of the vehicle body yaw rate γ, the vehicle body lateral acceleration Yg, or the vehicle body slip angle β, it is possible to suppress the aforementioned control divergence. Therefore, in this travel locus control device, when the detection accuracy of the travel lane information is lower than the reference detection accuracy or when the detection of the travel lane information is interrupted, the vehicle body yaw rate γ, the vehicle body lateral acceleration Yg, or the vehicle body slip angle β Of these, at least one damping (attenuation) may be configured to be higher than that in the normal state. For this purpose, for example, at least one damping (attenuation) among the target vehicle body yaw rate γ _tgt , the target vehicle body lateral acceleration Yg _tgt or the target vehicle body slip angle β _tgt may be increased from that in the normal state. As another method, the damping of the driving support system (at least one of the VGRS system, the EPS system, or the ARS system) may be increased from that in the normal state. Even in this case, as the detection accuracy of the travel lane information is lower than the reference detection accuracy or the frequency at which the detection of the travel lane information is interrupted increases, the vehicle body yaw rate γ, the vehicle body lateral acceleration Yg or the vehicle body during the travel locus control is increased. It is desirable to raise at least one of the slip angles β higher than in the normal state.

  In addition, the travel locus control device cannot execute all of the first to sixth methods because the vehicle behavior cannot be maintained in a stable state, for example, and the vehicle body yaw rate γ, the vehicle body lateral acceleration Yg, If all the control responsiveness of the vehicle body slip angle β cannot be increased, or if all the damping of the vehicle body yaw rate γ, the vehicle body lateral acceleration Yg, and the vehicle body slip angle β during the travel locus control cannot be increased, the travel locus It is desirable to reduce the vehicle speed while continuing the control. Thereby, this traveling locus control apparatus can continue traveling locus control, avoiding the departure of a lane.

  Here, the travel locus control is stopped or interrupted by the driver's intention (such as the operation of the switch described above). In that case, it is desirable to increase at least one of the yaw rate gain Gγ, the lateral acceleration gain Gyg, or the slip angle gain Gβ. In other words, the electronic control device 1 includes a vehicle according to the driver's steering operation by increasing at least one of the target yaw rate gain, the target lateral acceleration gain, or the target slip angle gain in the above-described Expression 1-3. It is desirable to control the behavior to be large. In addition, when the traveling locus control is stopped or interrupted by the driver's intention, the steering assist torque of the EPS system may be increased so as to obtain a light steering feeling.

  When the detection accuracy of the travel lane information is better than the reference detection accuracy, the better the detection accuracy, at least of the vehicle body yaw rate γ, the vehicle body lateral acceleration Yg, or the vehicle body slip angle β during the travel locus control. One control responsiveness or damping may be lowered than in the normal state. Thereby, for example, since power consumption can be reduced, fuel efficiency is improved.

DESCRIPTION OF SYMBOLS 1 Electronic controller 10 Vehicle 21 Steering wheel 22 Steering shaft 30 Steering torque generator 40 Front wheel steering device 42 Actuator 50 Rear wheel steering device 52 Actuator 61 Imaging device 71 Yaw rate sensor 72 Car body lateral acceleration sensor Wfl, Wfr Front wheel Wrl , Wrr Rear wheel

Claims (3)

In a traveling locus control device that detects traveling lane information of the host vehicle in front of the vehicle and controls the vehicle based on the traveling lane information.
When the detection accuracy of the travel lane information is lower than the reference detection accuracy, or when the detection of the travel lane information is interrupted, compared to the case where the travel lane information of the reference detection accuracy is detected, the travel locus control is being performed. A travel trajectory control device characterized by increasing at least one of control response or damping of the vehicle body yaw rate, vehicle body lateral acceleration, or vehicle body slip angle.   The travel locus control apparatus according to claim 1, wherein the control responsiveness or the damping is increased as the detection accuracy of the travel lane information is lower than the reference detection accuracy.   The travel locus control device according to claim 1, wherein when the control responsiveness and the damping cannot be increased, the vehicle speed is decreased.

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